Electric furnace



M. RUTHENBURG.

ELECTRIC FURNACE.

APPLICATION FILED MAY 4. 19m,

Patented Mar. 30

MARCUS RUTHENBURG, OF BUFFALO, NEW YORK.

ELECTRIC FURNACE.

Specification of Letters Patent.

Patented Mar. 30, 1920.

Application filed May 4, 1918. Serial No. 232,425.

To all whom it may concern:

Be it known that I, Marcus RUTHEN- BURG, citizen of the United States of America, residing at Buffalo, county of Erie, and State of NewYork, have invented certain new and useful Improvements in Electric Furnaces, of which the following is a specification.

This invention relates to electric furnaces, and has for its chief object the provision of an improved electric furnace of the resistance type, including an element. insulated from the object to be treated within the furnace, but capable of transforming electrical energy into heat and transmitting heat to the interior of the furnace.

More particularly it is an object of this invention to provide an improved heating element, which will transform electrical energy into heat in a very effective manner, and will give out the heat thus acquired to parts of the furnace where the heat is to be applied.

Another object of the present invention is to provide an electric furnace of the resistance type which is adapted for the reduction of certain elements from their compounds.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein preferred embodiments of the present invention are clearly shown.

Referring to the drawings, Figure 1 is a vertical cross-sectional view of one type furnace embodying the present invention;

Fig. 2 is a longitudinal sectional View;

Fig. 3 is a vertical cross-sectional view of a modified form showing a resistance element arranged for direct current or singlephase alternating current electricity;

Fig. 4 is a cross sectional view of a modified form of electric furnace including a resistance element arranged for operation with a three-phase alternatmg current, said view also including a wiring diagram showing cornections with a three-phased generator; an

Fig. 5 is a longitudinal sectional view of an electric furnace of the resistance type adapted for the reduction of certain elements from their compounds.

Referring to the Figs. 1 and 2, 2O designates an inner shell of fire-clay or other refractory material which is located concentrically with an outer shell 21 or similar material. The annular chamber between the shells 21 and 20 provides a space for the heating element which consists of carbonblock electrodes 22 and 23 insulated from each other by means of block 24:, and a plurality of carbon rods 25 which are packed in as close as possible in contact with one another and with the electrodes 22 and 23. The spaces between the rods and the shells 20 and 21 are filled with more or less finely divided carbonaceous material, as per example, powdered graphite indicated by the small dots shown at 26. ,27 designates a jacket of heat insulating material surrounding the furnace, except at the front end thereof which is closed by a door 28 supported by a lever 29 carrying a counterbalance 30. The jacket27 may be'inclosed by a sheet-iron jacket 31.

The operation of the furnace shown in Figs. 1 and 2 is as follows: Electrodes 22 and 23 are connected by means of conductors 34 and 35 with a source of current not shown, and current will pass from electrode 22, and from one carbon rod to the one adjacent, and finally around the entire space between shells 20 and 21 to the carbon electrode 23. Due to the resistance afiorded by the series of carbon rods to the passage of electric current, one rod will begin to be heated along the line of contact with an adjacent rod, and finally, as the current continues to flow, the entire series of carbon rods will become a glowing mass of material transferring electrical energy into heat which is conducted through the wall of the inner shell to the interior of the furnace where heat may be applied to any substance which is to be heat treated in the furnace. By virtue of the powdered graphite which fills the space between the carbon rods, practically no air can come in contact with the resistance element, hence oXidization of the carbon rods is practically eliminated.

Fig. 3 shows a cross-sectional view of a furnace which is practically the same in construction as that described above, with the exception that the shells 20 and 21 are cylindrical in form.

The furnaces thus far described are designed to be used with direct current or a single-phase alternating current electricity. "When it is desired to use a three-phase alternating current, three carbon electrodes 40, 41, and 42, are spaced 120 apart within the annular chamber between the shells 20 and 21, the remaining space being filled with the carbon rods 25 and powdered graphite 26 which has just been described. Electrodes 40, ll and I2 are connected by means of wires 43, 44 and 5 with the armature circuits of a three-phase generator &6 having a field winding 47 and a separate exciter 48. In a furnace of this type, the three components of the alternating current will surge back and forth between the electrodes 40, 4.1 and 42, and cause the carbon rods to be heated in the same manner as in a furnace of the direct current or the single-phase alternating current type.

Fig, 5 shows a furnace for the reduction of certain elements from certain compounds, such as metals from their oxids, said furnace embodying the present invention. This furnace is substantially the same in construction as the furnace shown in Fig. 2, except that it rests on a foundation with its longitudinal axis at an angle with the horizontal. A drum 50 having hollow journals 51 and 52 is supported concentrically with the shell 20 by means of bearing brackets 53 and 54, and is adapted to be rotated by means of a rotatable shaft 55 connected with a source of power, not shown, and carrying a driving gear 56 meshing with a driven gear 57 carried by journal 52. The reducing agent such as illuminating gas may be'introduced at the lower end of the drum 50 through the pipe 58. The

drum 50 being revolved in the manner described, the oxid to be reduced and the reducing agent will be brought into intimate contact and heated to the desired degree. by means of the heat passing from the resistance element through the walls of shell 20 and into the drum 50. The gaseous products of the reaction taking place within the drum will pass out the journal 51.

While the forms of mechanisms herein shown and described constitute preferred forms of embodiments of the invention, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What I claim is as follows 1. In an electric furnace, the combination with a shell of heat-transmitting material; of a resistance element surrounding said shell and substantially coextensive with the outer surface thereof, said element comprising a plurality of members individually removable from the furnace for replacement.

2. In an electric furnace, the combination with a shell of refractory material of a resistance element including a plurality of laterally contacting carbon rods surrounding the shell, and a heat insulating jacket surrounding the resistance element.

3. In an electric furnace, the combination with a shell of refractory material of a resistance element including a plurality of laterally contacting carbon rods surrounding the shell, means to prevent oxidization of the carbon rods, and a heat insulating jacket surrounding the resistance element.

4. In an electric furnace, the combination with a shell of refractory material. of a resistance element including a plurality of contacting carbon rods surrounding the shell, a quantity of powdered graphite packed into the spaces between the rods, and a jacket of heat insulating material surrounding the resistance element.

5. In an electric furnace, the combination with concentrically disposed inner and outer shells of refractory material, of a resistance element between the inner and outer shells including a plurality of contacting carbon rods, a quantity of powdered graphite packed into the spaces between the rods, and a jacket of heat insulating material surrounding the outer shell.

6. In an electric furnace, the combination with a shell, of a resistance element consisting of a plurality of carbon rods surrounding the shell, and a drum mounted to rotate within the shell and means providing for the entrance and exit of a fluid from the drum.

7 In an electric furnace, the combination with a shell of heat-transmitting material, of a resistance element comprising a'plurality of individually removable members, said resistance element providing. for the passage of current once around the shell.

8. In an electric furnace, the combination with a refractory heating wall of. a 'substantially continuous electrical heating element arranged in substantially uniform heating relation with said wall, said element comprising a plurality of laterally contacting rods of conducting material.

9. In an electric furnace, the combination with a refractory heating wall of a substantially continuous electrical heating element arranged in substantially uniform heating relation with said Wall, said element comprising a plurality of laterally contacting carbon rods.

10. In an electric furnace, the combination with a shell of heat-transmitting material; of 'a resistance element surrounding said shell and substantially coextensive with the outer surface thereof, said element providing for the passage of current once around the shell. In testimony whereof I affix my signature in presence of two. witnesses.

MARCUS RUTHENBURG.

Witnesses:

EDWARD P. LEVIN, LOUISE M. HORLEIN. 

